TY - JOUR
T1 - Arsenic remediation of drinking water using iron‐oxide coated coal bottom ash
JF - Journal of Environmental Science and Health, Part A
Y1 - 2010/08//
SP - 1446
EP - 1460
A1 - Johanna L. Mathieu
A1 - Ashok J. Gadgil
A1 - Susan E. Addy
A1 - Kristin Kowolik
KW - arsenic
KW - bangladesh
KW - coal bottom ash
KW - drinking water
KW - water contaminants
KW - water treatment
AB - We describe laboratory and field results of a novel arsenic removal adsorbent called ‘Arsenic Removal Using Bottom Ash’ (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (∼ $0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community-scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R2 = 0.77) ARUBA's adsorption capacity in treating real groundwater is 2.6 × 10− 6mol/g (0.20 mg/g). Time-to-90% (defined as the time interval for ARUBA to remove 90% of the total amount of arsenic that is removed at equilibrium) is less than 1 hour. Reaction rates (pseudo–second-order kinetic model, R2 ≥ 0.99) increase from 2.4 × 105 to 7.2 × 105 g mol− 1min− 1 as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA's arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA's AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to be less expensive than filtration of micron-scale particles, further contributing to the affordability of a community-scale water treatment center.
VL - 45
IS - 11
DO - 10.1080/10934529.2010.500940
ER -